Tilting furnace



Jam-30, 1945.

M. TAMA ET AL.

TILTING FURNACE Filed Jan. 3, 1944 3 Sheets-Sheet l www* ATTORNEY.

Jan. 30, 1945i M. TAMA ET Al. 2,368,173

TILTING FURNACE Filed Jan. 5, 1944 3 Sheets-Sheet 2 INVEN TORS.r

Jan. 30, 1945,

M. TAMA ETAI.

TILTING FURNACE Filed Jan. 3, 1944 3 Sheets-Sheet 3 ai 6% g Q: Q t INVENTORS `Q L di( l T BY x2- 17o/f( @fm ATTORA/E',

Patented Jan. 30, 1945 UNITED STATES APATENT OFFICE TILTING FURNACE Mario Tama, Morrisville, Pa., and James Lloyd Hoff, Pennington, N. J., assigner-s to Ajax Engineering Corporation. Trenton. N. J.

Application January s. 1944, serial No. 516,862

6 Claims.

from the pouring crucible or furnace for the.

entire period of operation.

It, therefore, is the main object of the invention to provide a tilting furnace which will pour a constant equal amount of metal per time unit.

It is also an object of this invention to achieve in addition to the pouring of equal constant quantities of the molten charge a substantially residueless discharge, this term being used to indicate that the upper hearth is practically emptied out, but that the melting chanels and the bottom groove of the hearth remain filled with molten metal, as otherwise the secondary circuit would be interrupted and the further operation of the furnace impaired.

It is a further object of the invention to construct a furnace of this type where the metal may be poured with a uniform angular speed about its pivot point during the entire cycle of operation.

It is a further important object of the invention to eliminate any manual control of the angular tilting velocity and 4to hereby greatly save the incumbent expenses.

It is another object of the invention to provide means whereby a nose-tilting furnace can be tilted very slowly and at a constant angular speed about the pouring spout.

It is also an object of the invention to provide a tiltable furnace where in equal times equal angles are displaced starting from the original position. y

It is an important object of the invention to assure absolute accuracy of the pouring operation.

Another purpose of the invention is to provide a shape of the upper part of the furnace crucible which may be rammed in a simple manner.

With these and other objects in view which will become apparent as this specification proceeds. the furnace embodied in this invention is illustrated by way of example in the attached drawings.

In the drawings Fig. 1 shows a vertical sectional view of the tilting furnace taken on line I-I of Fig. 2,

Fig. 2 is a vertical sectional view taken on line 2--2 of Fig. 1,

Fig. 3 is a horizontal sectional view taken on line 3-3 of Fig. 1,

Figs. 4, 5, 6, 7 are schematic views of the furnace crucible and Fig. 8 shows two curves relied upon to explain the mathematic principles upon which the instant furnace construction is based.

In the embodiment of our invention shown in the drawings I designates a housing containing crucible 2 adapted to hold the molten metal and vprovided with a refractory lining 3.

i spout; the tilting axis is indicated at x.

' chamber I3 is created which communicates with crucible 2 through passage I4. The partition l prevents the slag forming a surface layer on the melt from passing into the spout chamber I3.

The characterizing feature of the furnace resides in the provision of slanting plane II or of combined slanting planes II and I2 intersecting the lower portion of the cylinder whereby ungulae are formed, these slanting walls rendering it `possible to realize the previously recited important objects of the invention.

In conformity. with these objects the instantv furnace construction is Abased on the following considerations:

If the cylindrical vessel A with radius R is rotated about axis B through an angle the volume of liquid poured is equal to the volume of the cylinder above the horizontal line C. 'Ihis volume is equal to R3 tan 9i.

Since the rate of increase of qb is to be constant, the volume poured during any instant is proportional to the tangent of the corresponding angle.

If o can be made to never exceed some relative small angle, the error introduced because of the change in the rate on increase of the tangent will be unimportant.

This, however. is highly impractical because the cylinder then would have to be of large diameter with an accompanying large metal surface and excessive overall dimensions and costs of installation and operation.

If. however, the lower part of the cylinder is cut by a plane at an angle, the amount of metal poured will then vary not with the tan alone, but with some other function of the angle.

The direct solution of this problem was diillcult, and the following trial-in-error method was used:

The volumes poured at intervals of 5% were calculated and the curve (Fig. 8) plotted and checked against a straight line u.

Let i r==radius of cylinder V=volurne of liquid poured from plain cylinder.

Assume a value for a then Hz=ha Assume a value for b and g, then f=r+b Let `(at, u) be the rectangular coordinates of the intersection of line C and D with origin at point O. Then z1=f y1=g xz=2r y2=a y-i yi sg- -CU-wi) substituting :Pyiglesia but 11:3: tan (note that is negative) solving these two equations simultaneously gives :i: in l* Referring now to Fig. 5

sin u=a/r from which the radian measure of u can be determined. let W=totai amount poured from crucible,

W is now calculated for intervals of 5 degrees and the curve plotted. The deviation of the curve from a straight line indicates the error in the rate of pour.

In plotting the curve a: shown in Fig. 8 3'7 1/2 degrees is taken as of the total tilted arc and 3266 cubic inches is taken as 100% of the total volume poured.

The first point of the curve plotted was for 2*/2 degrees and 208 cubic inches.

100 (Z2/37.5) :6.66% equal to percentage of total arc traveled 100 (208/3266) :6.4% equal to percentage of total volume poured.

This procedure was repeated for all points calculated and a connecting curve :l:A was drawn through the points.

Finally a straight line 4 was drawn between 0% total arc, 0% total volume and 100% total arc, 100% total volume.

The deviation of the plotted curve from the straight line indicates the difference between absolutely uniform pour and that actually achieved. In this case the error is approximately 1%.

It results that in intersecting the furnace by an inclined plane in accordance with the above consideration the previously recited objects of the invention may be satisfactorily realized.

Various changes may be made of the constructional details of the furnace disclosed in the foregoing speciilcation without departing from the spirit of the invention or sacrificing advantages thereof.

We claim:

l. In a tiltable induction furnace of a submerged resistor type for use in the continuous casting of metals a melting hearth composed of a cylindrical upper portion and of an ungula creating bottom portion, the said bottom portion being formed by at least one slanted wall inwardly converging from the lower 4edge periphery of the cylindrical upper portion in such a manner as to effect a constant uniform substantially residueless metal discharge throughout the entire pouring period under avoidance of changes of the angular speed.

2. In a tiltable induction furnace of a submerged resistor type for use in the continuous casting of metals a melting hearth composed of a cylindrical upper portion and of an ungula creating bottom portion, the said bottom portion formed by two opposite slanted walls inwardly converging from one half of the lower edge periphery of the cylindrical upper portion in such a manner as to effect a constant uniform substantialiy residueless metal discharge throughout the entirepouring period under avoidance oi changes of the angular speed.

3. In a tiltable induction furnace of a submerged resistor type for use in the continuous casting of metals a melting hearth composed of a cylindrical upper portion and of an ungula creating bottom portion, a pouring spout in the said upper portion, the said bottom portion being formed by at least one slanting wall located opposite to the pouring spout in such a manner as to effect a constant uniform substantially residueless metal discharge throughout the entire pouring period under avoidance of changes of the angular speed.

4. In a tiltable induction furnace of a submerged resistor type for use in the continuous casting of metals a melting hearth composed of a cylindrical upper portion and of an ungula creating bottom portion, the said bottom portion formed by two slanted walls, a pouring spout in the said upper portion, the one wall being located in symmetrical relation to the said pouring spout on the same side of the cylindrical upper portion and the second wall opposite thereto, the two slanted walls inwardly converging from one half of the lower edge periphery of the cylindrical upper section in such a manner as to effect a constant uniform substantially residueless metal discharge throughout the entire pouring period under avoidance oi' changes of the angular speed.

5. In a tiltable induction furnace of the submerged resistor type for use in the continuous casting of metals a melting hearth composed of a cylindrical upper portion, an ungulal provided bottom portion and a bottom groove, the said bottom portion being provided with two opposite slanting walls inwardly converging from one half of the lower edge periphery of the cylindrical upper portion towards said groove in such a, manner as to eiect a constant uniform substantially residueless metal discharge throughout the entire v pouring period under avoidance of changes of the angular speed.

6. In a. tiltable induction furnace of a submerged resistor' type for use in the continuous casting of metals a melting hearth composed of a, cylindrical upper portion and ungula provided bottom portion, the height of said upper portion being limited by the extent of the tilting movement of the hearth through an angle still permitting a constant uniform discharge, the said bottom portion being provided with slanting walls inwardly converging from the lower edge periphery of'the cylindrical upper portion towards the hearth bottom in such a. manner as to complete the constant'uniform substantially residueless metal discharge throughout the entire pouring period under avoidance of changes of the angular speed.

v MARIO TAMA.

J. LLOYD HOFF. 

